You can get the tarball from the link on our homepage or ask your friendly distribution packagers to package it for you. Some might already have done that anyway
To build from the tarball, you can follow the instructions from our wiki.
Please focus mainly on the new features listed in the article and in the ChangeLog as well as the features you use most, but please also have a look at the (still incomplete) list of tests. Feel free of course to add tests to that list, too.
We would be very glad if you could report the bugs you find right away by using this link: Enter Bug: amarok. Feel free to ping me (Mamarok) in #amarok on irc.freenode.net if you need more information.